The Detective Boys receive a letter by airmail when they visit the Moore Detective Agency. The letter was posted in Egypt, and the sender calls themselves Cleopatra. According to the contents, a 4500-year-old pharaoh's curse is in danger of being reawakened. To prevent this, the seven riddles described in the letter must be solved within a short time, all of which relate to pyramids. While Moore is already drunk in the afternoon and of no great help, Ran agrees to assist the children. The Detective Boys then set out to answer the seven questions posed in the letter...